The present invention relates to drilling and servicing equipment for oil and gas wells generally, and in particular relates to a trolley hoisting system for use in rigs which transport and/or operate equipment for continuous coiled tubing drilling, for conventional joined pipe handling and drilling, and/or for wireline applications.
Our U.S. Pat. No. 6,003,598 and corresponding Canadian Patent 2,235,555 for a xe2x80x9cMobile Multi-Function Rigxe2x80x9d disclose a dual winch arrangement atop a pivotable derrick, or masts, for performing various functions relating to drilling and servicing either oil or gas wells. One of the winch systems, namely the derrick or mainblock winch, is used to raise and lower certain equipment along the mast, such as an injector and lubricator for continuous or coiled tubing (referred to herein as xe2x80x9cCTxe2x80x9d). A secondary, or fastline, winch is used to manipulate other equipment, such as a blow-out-preventer (xe2x80x9cBOPxe2x80x9d). For operations requiring use of a traveling block and elevators to lift and lower conventional joined pipe sections, the injector must first be brought to rest at the bottom of the mast and moved laterally out of the plane of the mast. The traveling block and the mainblock winch are then decoupled from the injector so that they are free to manipulate the joined pipe sections as in a conventional derrick.
We have not been able to locate or identify any conventional derricks, whether they use a single winch or a similar multiple (i.e. two or more) winch system, which would allow one winch arrangement to handle multiple tasks without having to decouple the winch from the injector and remove the injector from the mast, or where the injector superstructure is not thereafter interfering with movement of the mainblock winch lines and the joined pipe or other downhole equipment being handled. In particular, there are time and labour costs associated with handling of the injector upon switching tasks. Removal of the injector from the plane of the mast to enable access and use of a winch or hoisting system is labour and time consuming. The costs and difficulties are further augmented if the winch line moving the injector must also be disconnected or moved from the injector mechanism before using it for another desired task. Further, in a multiple winch system where the primary winch line is not disconnected from the injector, the secondary winch is typically slower and has less capacity than the primary line, leading to further inefficiencies.
What is desired therefore is a novel trolley hoisting system for use in rigs, particularly multi-task rigs, which transport and/or operate equipment for oil and gas operations, including continuous coiled tubing drilling and conventional joined pipe handling and drilling operations. The novel system should allow a single winch arrangement to perform various task without having to detach from or connect to the injector, as in some conventional rig arrangements, when switching between tasks. In particular, the winch system should be capable of moving the injector along the rig""s derrick and, upon fixing the injector at a desired location along the derrick, the winch should be immediately available for performing other desired tasks, such as a joined pipe operation.
According to the present invention, there is provided in one aspect a trolley hoisting system for use in a rig comprising a winch line extending from an upper end of a rig derrick having a traveling block at a lower end thereof, and an injector housing having at least one cavity for allowing the winch line passage therethrough and being adapted to engage the traveling block so that the winch line may be used to raise and lower the injector and injector housing along the derrick, and a lock arrangement for fixing the injector housing to the derrick at an upper end thereof to allow the traveling block to extend below the injector housing for performing other desired tasks on the rig.